CN101931902A

CN101931902A - Service implementation method and system of IP multimedia subsystem network

Info

Publication number: CN101931902A
Application number: CN2009101422601A
Authority: CN
Inventors: 陶全军; 谢振华; 郝振武
Original assignee: ZTE Corp
Current assignee: An Caihong
Priority date: 2009-06-26
Filing date: 2009-06-26
Publication date: 2010-12-29
Anticipated expiration: 2029-06-26
Also published as: WO2010148783A1; CN101931902B

Abstract

A service implementation method of an internet protocol (IP) multimedia subsystem network comprises the following steps: after receiving a request for providing the roaming number, which carries the number of user equipment (UE) and is sent by the home network of the UE, an enhanced mobile switch center (E-MSC) returns the roaming number corresponding to the number of the UE and pointing at E-MSC to the home network of the UE; after receiving the initial address message which is sent by a public switched telephone network (PSTN) in which the calling user is located and carries the roaming number, the E-MSC uses the number of the UE as the called number and sends the session invitation message to the UE through the serving call session control function (S-CSCF) and the proxy call session control function (P-CSCF); after receiving the ringing message of the session initial protocol (SIP), which is sent by the UE, the E-MSC sends the address complete message to the PSTN; after receiving the response message of the SIP, which is sent by the UE, the E-MSC connects the IP media bearer between the E-MSC and the UE with the circuit switched (CS) media bearer between the E-MSC and the PSTN and sends the response message of the circuit domain to the PSTN to complete establishment of the IMS service session.

Description

A kind of service implementation method of IP Multimedia System network and system

Technical field

The present invention relates to the communications field, relate in particular to the service implementation method and the system of a kind of IP (Internet Protocol, Internet Protocol) multi-media subsystem network.

Background technology

In order to keep third generation partner program (3rd Generation Partnership Project, abbreviate 3GPP as) in the competitiveness of moving communicating field, 3GPP is just endeavouring research at present to packet switched core network (Packet Switched Core, abbreviate PS Core as) and global system for mobile communications wireless access network (Universal Mobile Telecommunication System Radio Access Network, abbreviate UTRAN as) evolution, purpose is to make the PS Core (being called for short EPC) of evolution that higher transmission rate can be provided, shorter transmission delay, and support E-UTRAN (Evolved UTRAN, the UTRAN of evolution), GERAN (GSM EDGE radio access network, global system for mobile communications enhanced data rates global system for mobile communications evolution technology wireless access network), UTRAN, mobile management between WLAN (Wireless Local Area Network, WLAN (wireless local area network)) and other non-3 GPP access network network.The mobile communication system of this evolution is called as the grouping domain system (Evolved Packet System abbreviates EPS as) of evolution.

Present stage, speech business is the important revenue source of mobile operator, therefore, how to guarantee to realize that the high-quality speech business is extremely important in EPS.At present, everybody relatively pays close attention to and adopts voice-based Traditional IP IP multimedia subsystem, IMS (IMS) to realize speech business.

Fig. 1 is the IMS network architecture schematic diagram of prior art, comprises following network element:

101: subscriber equipment (User Equipment abbreviates UE as), the P-CSCF that is used for being linked into by access device the IMS network registers, and sets up session connection with far-end;

102: Proxy Call Session Control Function (Proxy Call Session Control Function abbreviates P-CSCF as) is used to carry out the route of message, and sets up Security Association with UE;

103: query call conversation control function (Interrogating Call Session Control Function, abbreviate I-CSCF as), be used for and HSS (Home Subscriber Server, home subscriber server) mutual, request HSS is that UE distributes S-CSCF, or the pairing S-CSCF of inquiring user;

104: service call conversation control function (Serving Call Session Control Function abbreviates S-CSCF as) is used to the user that functions such as registration, calling control are provided;

105: home subscriber server (HSS) is used to preserve user's subscription data, for calling out or session provides support.

Adopt framework shown in Figure 1, when user/UE was in roaming state, UE registered to home network by the P-CSCF that is linked into visit ground; After succeeding in registration, if user's initiation session business, UE sends session invitation message to home network, by the S-CSCF of home network the session invitation message is transmitted to the called subscriber, and session control is finished by home network.

Under the situation of IMS network partial deployment, if the user roams into the IMS network on visit ground, and the go-between between the IMS network on the IMS network of ownership place and visit ground is not disposed the IMS network, then might be (for example with the message of UE, registration message, session invitation message) be routed to home network, cause the IMS service fail; Equally, home network mails to the also possibly IMS network that can't be routed to visit ground of message (for example, session invitation message) of UE.

Summary of the invention

Technical problem to be solved by this invention is, overcomes the deficiencies in the prior art, and a kind of service implementation method and system of IMS network is provided, to be implemented in local IMS network to the visitor being the exchange that called subscriber's calling realizes signaling and medium.

In order to address the above problem, the invention provides a kind of service implementation method of IP Multimedia System network, when the user equipment (UE) that is in roaming state by local IP Multimedia System IMS network Proxy Call Session Control Function P-CSCF and service call conversation control function S-CSCF after the E-MSC of enhancing mobile switching centre of local IMS network successfully registers, this method comprises:

After receiving the request of Providing Roaming Number of the number that carries described UE that the home network of described UE sends, the roaming number that described E-MSC will be corresponding with the number of described UE, point to described E-MSC returns to the home network of described UE;

After receiving the initial address message that carries described roaming number that the public switch telephone network PSTN at calling subscriber place sends, described E-MSC as called number, sends session invitation message by described S-CSCF and P-CSCF to described UE with the number of described UE;

After receiving the ALERTING message of the initial session protocol SIP that described UE sends, described E-MSC sends the address to described PSTN and finishes message; And after the response message of the SIP that receives described UE transmission, IP media bearer between described E-MSC and the described UE and described E-MSC are linked to each other with circuit switching (CS) media bearer between the described PSTN, and, finish the foundation of IMS session service to the response message in described PSTN transtation mission circuit territory.

In addition, after described E-MSC receives described initial address message, also call out control, call out control and finish the described session invitation message of back transmission according to the user data of the described UE of this locality storage.

In addition, described E-MSC obtains and stores the user data of described UE in the following way:

In the registration process of described UE, receive the register requirement of described S-CSCF transmission as described E-MSC after, home subscriber server HSS or attaching position register HLR to the home network of described UE send position updating request, to obtain the user data of described UE;

After receiving described position updating request, described HLR or HSS return to described E-MSC with the user data of described UE;

Described E-MSC stores the user data of described UE.

In addition, described E-MSC sets up described IP media bearer by sending described session invitation message.

In addition, described E-MSC and described PSTN finish the described CS media bearer of setting up alternately of message by described initial address message and address.

The present invention also provides a kind of business realizing system of IP Multimedia System network, and this system provides professional as visited network for the UE that is in roaming state; This system comprises: P-CSCF, S-CSCF, E-MSC; Wherein:

Described E-MSC is used for after the request of Providing Roaming Number of the number that carries described UE that the home network that receives described UE sends, and roaming number will be corresponding with the number of described UE, that point to described E-MSC returns to the home network of described UE;

Described E-MSC also is used for behind the initial address message that carries described roaming number that the PSTN that receives the calling subscriber place sends, and the number of described UE as called number, is sent session invitation message by described S-CSCF and P-CSCF to described UE;

Described E-MSC also is used for sending the address to described PSTN and finishing message behind the ALERTING message of the SIP that receives described UE transmission; And after the response message of the SIP that receives described UE transmission, IP media bearer between described E-MSC and the described UE and described E-MSC are linked to each other with CS media bearer between the described PSTN, and, finish the foundation of IMS session service to the response message in described PSTN transtation mission circuit territory.

In addition, described E-MSC also is used for after receiving described initial address message, calls out control according to the user data of the described UE of this locality storage, calls out control and finishes the described session invitation message of back transmission.

In addition, described E-MSC also is used for the registration process at described UE, after receiving the register requirement of described S-CSCF transmission, HSS or HLR to the home network of described UE send position updating request, obtaining the user data of described UE, and store the user data of the described UE that described HLR or HSS return.

In sum, the present invention strengthens mobile switching centre (E-MSC) by being provided with in local IMS network, when visitor after E-MSC successfully registers, by E-MSC at local IMS network to the visitor being the exchange that control and signaling and medium are called out in called subscriber's calling.

Adopt IMS network local deployment framework provided by the invention, and adopt the EPS network insertion to realize the system and method for CS business, solve the roaming problem of former IMS network partial deployment, adopt the IMS of standard to access terminal simultaneously, reduce user's overlapping investment because of the network evolution process.

Description of drawings

Fig. 1 is the IMS network architecture schematic diagram of prior art;

Fig. 2 is the Organization Chart one of the business realizing system of embodiment of the invention IMS network;

Fig. 3 is the Organization Chart two of the business realizing system of embodiment of the invention IMS network;

Fig. 4 carries out the process registration flow chart for adopting system architecture of the present invention;

Fig. 4 a inserts local IMS network, when initiating registration by local IMS network, selects the first method flow chart of local IMS network for this UE/ user as UE;

Fig. 4 b inserts local IMS network, when initiating registration by local IMS network, selects the second method flow chart of local IMS network for the user of this UE as UE;

Fig. 4 c inserts local IMS network, when initiating registration by local IMS network, is selected the method flow diagram of local IMS network by UE as UE;

Fig. 4 d is that E-MSC receives the method flow diagram that obtains the IMSI of respective user after the login request message;

Fig. 5 is the Organization Chart three of the business realizing system of embodiment of the invention IMS network;

Fig. 6 works the method flow diagram of exhaling for adopting system architecture of the present invention;

Fig. 7 carries out the method flow diagram of exhaling eventually for adopting system architecture of the present invention.

Embodiment

Core concept of the present invention is, in local IMS network, be provided with and strengthen mobile switching centre (E-MSC), when being in user's (being called visitor) under the roaming state after E-MSC successfully registers, by E-MSC at local IMS network to the visitor being the exchange that control and signaling and medium are called out in called subscriber's calling.

Describe the present invention below in conjunction with drawings and Examples.

Fig. 2 is the Organization Chart one of the business realizing system of embodiment of the invention IMS network, comprising:

201: subscriber equipment (User Equipment abbreviates UE as); Possess the IMS ability, support Session Initiation Protocol, the P-CSCF that is used for being linked into by access device the IMS network registers, and sets up session connection with far-end;

202: strengthen (the Enhanced Mobile Switch Center of mobile switching centre, abbreviate E-MSC as) server, be the newly-increased network element of the present invention, E-MSC server (abbreviating E-MSC as) is a physical entity, possess circuit switching (exchange of media) ability and signaling protocol transfer capability, and the ISC interface and the Cx interface of support standard are registered in this locality that can realize visitor.

For local IMS network, E-MSC has realized the function of HSS and AS (application server); From the angle of CS network, E-MSC has realized the function of MSC.

Specifically, E-MSC possesses following function:

Possess protocol conversion function, can be to changing mutually between SIP signaling and the circuit domain related protocol signaling, can convert the SIP signaling of receiving from ISC interface and Cx interface to corresponding circuit domain signaling;

Possess mobile exchange capacity (being signaling and exchange of media ability), can between IP carrying and circuit domain carrying, carry out exchange of media;

Go into to call for when asking (being final call request) when what E-MSC received that remote subscriber initiates, can invite request to roaming in local IMS terminal initiation session as the user agent;

Possess local registration ability, when receiving the query messages that I-CSCF sends, can distribute local S-CSCF for visitor; When receiving the register requirement of visitor, can obtain corresponding IMSI (International Mobile Subscriber Identifier, international mobile subscriber identity) according to the IMS private user identity that carries in the register requirement; If local user data of no use can be obtained user data to the HSS/HLR of user attaching network;

Can generate the trigger criteria (be also referred to as initial filter standard or norm, promptly Initial Filter Criteria abbreviates iFC as) of E-MSC and trigger address (being the address of E-MSC);

When receiving the request that Provides Roaming Number of HSS/HLR transmission, E-MSC can distribute the roaming number that points to this locality;

When receiving setup requests (for example, session invitation message, initial address message), possesses the ability of carrying and carrying out medium and signaling exchange for this call setup.

203: CSCF (Call Session Control Function, abbreviate CSCF as), can be further divided into: query call conversation control function (Interrogating CSCF, abbreviate I-CSCF as), Proxy Call Session Control Function (Proxy Call Session Control Function, abbreviate P-CSCF as) and service call conversation control function (Serving CSCF abbreviates S-CSCF as).Wherein:

P-CSCF is used to carry out the route of message, and sets up Security Association with terminal; In addition, P-CSCF can route the request to the I-CSCF of local IMS network after receiving the register requirement of visitor;

I-CSCF is used for E-MSC mutual, and request E-MSC distributes S-CSCF for the user, or the residing S-CSCF of inquiring user;

S-CSCF is used to the user that functions such as registration, calling control are provided.

204: attaching position register (Home Location Register abbreviates HLR as) or home subscriber server (Home Subscriber Server abbreviates HSS as);

HSS/HLR is used to preserve user's subscription data, for calling out or session provides support, and when receiving the position updating request that E-MSC sends user data is returned to E-MSC.

HLR can think the subclass of HSS, be traditional CS (Circuit Switched, circuit switching) territory and PS (Packet Swithed, packet switching) territory service, HLR can unify with HSS, is positioned at same physical entity, also can be positioned on the different physical entities, exist interface between HLR and the HSS this moment, realizes the mutual of information.

Fig. 3 is the Organization Chart two of the business realizing system of embodiment of the invention IMS network, comprise the operation system that adopts IMS network of the present invention in this Organization Chart and registered related network element, wherein show each network element in the abridged access network part among Fig. 2: Mobility Management Entity (Mobility Management Entity, abbreviate MME as), gateway (Serving Gateway, abbreviate S-GW as), packet data network gateway (Packet Data Network Gateway, be called for short PDN GW or P-GW), Dynamic Host Configuration Protocol server (Dynamic Host Configuration Protocol Server abbreviates DHCP Server as); And show abridged domain name system among Fig. 2 (Domain Name System abbreviates DNS as); In addition CSCF further is subdivided into P-CSCF, I-CSCF and S-CSCF; Wherein:

Mobility Management Entity (MME) is the chain of command entity, be used for interim storing subscriber information, and be in charge of and store the UE context (such as the UE/ user ID, mobility management states, user security parameters etc.), for the user distributes temporary mark, when quartering at this tracing area or this network, is responsible for UE this user is carried out authentication;

Gateway (S-GW) is a user entity, is responsible for carrying out the route processing of user face data;

Packet data network gateway (P-GW) is the gateway that UE inserts PDN (Packet Data Network, Packet Data Network).When P-GW receive that UE sends obtain P-CSCF full name message the time, will return to UE from P-CSCF full name that Dynamic Host Configuration Protocol server gets access to.

P-GW and S-GW can close and be located in the physical entity.

Domain name system (DNS) is used for domain name is translated as corresponding IP address.

Dynamic Host Configuration Protocol server (DHCP Server) is used for P-CSCF full name or address dynamically are provided, and dns address is provided.

The concrete function of each network element shown in Figure 3 also will be described in more detail below.

Fig. 4 carries out the process registration flow chart for adopting system architecture of the present invention; In this flow process, after E-MSC receives the login request message that S-CSCF transmits,, then initiate position updating request, to obtain user data to HSS/HLR if there is not corresponding user data among the E-MSC; User data returns registration reply to S-CSCF after obtaining successfully, comprises trigger criteria (be also referred to as initial filter standard or norm, promptly Initial Filter Criteria abbreviates iFC as) and triggering address that E-MSC generates in this response message; As shown in Figure 4, this method comprises the steps:

401, UE sends login request message to the P-CSCF of local IMS network (be the P-CSCF of visited network, abbreviate local P-CSCF as) under roaming state, carries User Identity in this message;

402, after local P-CSCF receives login request message, this forwards is given the I-CSCF (be the I-CSCF of visited network, abbreviate local I-CSCF as) of local IMS network;

Can adopt several different methods that above-mentioned login request message is transmitted to local I-CSCF among the present invention, particular content can vide infra to the description part of Fig. 4 a～4c.

403, after local I-CSCF receives login request message, send query messages to the E-MSC of local IMS network, with the address of inquiry S-CSCF;

404, E-MSC assigns the address of the S-CSCF (abbreviating local S-CSCF as) of a local IMS network, and it is returned to local I-CSCF;

405, local I-CSCF sends login request message to local S-CSCF;

406, after local S-CSCF receives login request message, send login request message to E-MSC;

407, receive login request message after, if there is not corresponding user data among the E-MSC, then send position updating request, to obtain user data to the HSS/HLR of UE home network;

If corresponding user data is arranged among the E-MSC, then E-MSC is designated UE (user) registered, and return registration reply message to local S-CSCF, the trigger criteria of carrying the E-MSC generation in this message (is also referred to as initial filter standard or norm, be Initial Filter Criteria, abbreviate iFC as) and trigger address (being the address of E-MSC), and jump to step 412;

Comprise in the above-mentioned trigger criteria: the trigger criteria of incidents such as registered events, caller incident, called event.Wherein, the trigger criteria of registered events can trigger local S-CSCF and carries out third-party registration.

Comprise in the user data: information such as customer position information, CAMEL-Subscription-Information, business datum.

In this step, E-MSC need use user's IMSI (International Mobile Subscriber Identifier, international mobile subscriber identity) obtains user data, if the user ID in the login request message is not IMSI, then E-MSC can adopt several different methods to obtain user's IMSI, and concrete grammar can vide infra to the description part of Fig. 4 d.

408, HSS/HLR sends to E-MSC and inserts user data requests, carries the user data of respective user in this message, comprises the user in the user data circuit domain business data signed (abbreviating user's circuit domain service data as);

409, E-MSC preserves the user data that receives, and returns user data to HSS/HLR and inserts response message;

410, after HSS/HLR receives that the user data of E-MSC transmission inserts response message, upgrade response message to the E-MSC home position;

411, after E-MSC received position update response information, identifying user was registered, and returned registration reply message to local S-CSCF, carried trigger criteria (being iFC) and triggering address (being the address of E-MSC) that E-MSC generates in this message;

Comprise in the above-mentioned trigger criteria: the trigger criteria of incidents such as registered events, caller incident, called event.Wherein, the trigger criteria of registered events will trigger S-CSCF and carry out third-party registration.

412～414, local S-CSCF sends registration to UE and finishes message, and notice UE succeeds in registration;

415, S-CSCF sends third-party registration request, the user ID of carrying UE in this request, and the current access address of UE according to the registered events trigger criteria among the iFC to E-MSC;

416, after E-MSC receives the third-party registration request, preserve user ID and the current third party's log-on messages such as access address of UE of UE, and return registration to local S-CSCF and finish message.

It should be noted that step 415～416 are optional step; E-MSC preserves the current access address of UE so that at follow-up realization business continuance; The concrete grammar of realizing business continuance has exceeded category of the present invention.

Fig. 4 a inserts local IMS network, when initiating registration by local IMS network, selects first method (promptly the login request message that receives being transmitted to the method for local I-CSCF in the step 402) flow chart of local IMS network for this UE/ user as UE.In this flow process, be that the user selects local IMS network by the access network element P-CSCF of local IMS network.

In the prior art, P-CSCF can be transmitted to login request message the I-CSCF of home network according to the home domain name of carrying in this message after receiving login request message; And in the present embodiment, P-CSCF can according to carrier policy, directly be routed to local I-CSCF to login request message after receiving login request message, selects the E-MSC of local IMS network to register by local I-CSCF.

Shown in Fig. 4 a, this method specifically comprises following steps:

4a01 (being step 401), UE send login request message to local P-CSCF, carry home domain name and User Identity in this message;

4a02, receive login request message after, P-CSCF is according to User Identity and carrier policy, judge whether to select local IMS network (judging whether that promptly the login request message that will receive is transmitted to local I-CSCF and handles), concrete judgement and selection strategy can be:

All select local I-CSCF to transmit login request message (be about to local I-CSCF and be configured to unconditionally select local IMS network) for all users; Or

Judge according to operator's signing IMS interconnection agreement and User Identity whether respective user has signed the IMS interconnection agreement, select local I-CSCF to transmit login request message per family for the usefulness of not signing the IMS interconnection agreement; Can select the I-CSCF of this user attaching network to transmit login request message for the user who signs the IMS interconnection agreement.

4a03, when judge to need selecting local I-CSCF (promptly selecting local IMS network to carry out this locality registration), P-CSCF is to local I-CSCF forwarding login request message.

Fig. 4 b inserts local IMS network, when initiating registration by local IMS network, selects second method (promptly the login request message that receives being transmitted to the method for local I-CSCF in the step 402) flow chart of local IMS network for the user of this UE as UE.In this flow process, be that the user selects local IMS network by DNS.

In the prior art, P-CSCF need be according to the I-CSCF address of the home domain name of carrying in this message to DNS inquiring user ownership place after receiving login request message, and DNS can translate into this home domain name the address of the I-CSCF of a home network; And in the present embodiment, DNS can translate into home domain name the I-CSCF address of local IMS network according to carrier policy.

Shown in Fig. 4 b, this method specifically comprises following steps:

4b01 (being step 401), UE send login request message to local P-CSCF, carry home domain name and User Identity in this message;

4b02, receive login request message after, P-CSCF sends I-CSCF address lookup message to local dns, with the address of the I-CSCF of inquiry home network, carries the home domain name of carrying in the login request message in this query messages;

After 4b03, DNS receive above-mentioned query messages, carry out following processing according to carrier policy:

All home domain name are all translated into local I-CSCF address; Or

Sign the IMS interconnection agreement according to operator and judge whether the operator of the network of home domain name correspondence has signed the IMS interconnection agreement, and the home domain name that will not sign the network of IMS interconnection agreement all is translated as local I-CSCF address; The home domain name of signing the network of IMS interconnection agreement is translated into the address of the I-CSCF of corresponding home network;

4b04, DNS return to P-CSCF with the I-CSCF address.

Fig. 4 c inserts local IMS network, when initiating registration by local IMS network, is selected method (promptly making local P-CSCF in the step 402 login request message that receives is transmitted to the method for the local I-CSCF) flow chart of local IMS network by UE as UE.In this flow process, after UE obtains P-CSCF full name, home domain name is set according to P-CSCF full name.Flow process occurs in before the step 401 shown in Fig. 4 c, specifically comprises following steps:

4c01, UE send to P-GW and obtain P-CSCF full name message;

4c02, P-GW are from Dynamic Host Configuration Protocol server acquisition request P-CSCF full name;

4c03, Dynamic Host Configuration Protocol server return P-CSCF full name to P-GW;

4c04, P-GW return P-CSCF full name to UE;

After 4c05, UE receive P-CSCF full name,, then home domain name (soon the character string after " @ " character is set to home domain name in P-CSCF full name) is set according to P-CSCF full name if wish to use local IMS business; After this, in the login request message of UE in step 401 this home domain name is included in the login request message and registers, in step 402, local P-CSCF gives local I-CSCF according to the home domain name in the login request message with this forwards.

Fig. 4 d is that E-MSC receives the method flow diagram that obtains the IMSI of respective user after the login request message; This flow process has been described in the step 407 of Fig. 4, and E-MSC receives the method for obtaining the IMSI of respective user after the login request message, and shown in Fig. 4 d, this method comprises the steps:

4d01, receive login request message after, E-MSC extracts the user ID in this message, and judges whether user ID is IMSI, if not, execution in step 4d02 then, otherwise this flow process finishes;

If the 4d02 user ID is not IMSI, then E-MSC one of can be in the following way obtains corresponding IMSI:

Mode one: comprise following substep:

A1: if the interim private user identity that user ID is to use IMSI to derive, then E-MSC oppositely derives to interim private user identity, draws corresponding IMSI; Or

Mode two: comprise following substep:

B1: if user ID is the IMS private user identity, E-MSC can send the refusal registration message to UE, refuse this registration, and in this message, comprise the information that the indication user uses IMSI or uses the interim private user identity derived by IMSI to register;

After b2:UE receives the refusal registration message, use IMSI or use the interim private user identity of deriving by IMSI to initiate registration again according to the above-mentioned information that comprises in this message;

B3: after receiving the register requirement that UE resends, E-MSC obtains IMSI or obtains interim private user identity and it is oppositely derived from this request and obtains corresponding IMSI from this request; Or

Mode three: comprise following substep:

C 1:E-MSC to UE send that SIP (Session Initial Protocol, initial session protocol) subscribes to or the SIP query messages to obtain the IMSI of UE;

C2:UE returns user IMSI to E-MSC after receiving sip subscribe or SIP query messages; Or

Mode four: comprise following substep:

D1:E-MSC uses the IMS private user identity that carries in the register requirement to obtain corresponding IMSI to the HSS of UE home network;

D2:HSS returns the IMSI of IMS private user identity binding to E-MSC.

Fig. 5 is the Organization Chart three of the business realizing system of embodiment of the invention IMS network, related network element when having comprised the business realizing system that adopts IMS network of the present invention in this Organization Chart and calling out wherein shows each network element in the abridged access network part among Fig. 2: Mobility Management Entity (MME), gateway (S-GW), packet data network gateway (P-GW); And CSCF further is subdivided into P-CSCF and S-CSCF; In addition, also show the network element that the CS network among Fig. 2 is comprised in this Organization Chart: media gateway (Media Gateway, abbreviate MGW as), gateway MSC (Gateway Mobile Switching Center, abbreviate GMSC as), public switch telephone network (Public Switched Telephone Network abbreviates PSTN as); Wherein:

Media gateway (MGW) is used to provide media bearer;

Gateway MSC (GMSC) is used for carrying out signalling route when receiving initial address message;

(Public Switched Telephone Network PSTN), refers to fixed telephone network here to public switch telephone network.

The concrete function of each network element shown in Figure 5 also will be described in more detail below.

Fig. 6 works the method flow diagram of exhaling for adopting system architecture of the present invention; Exhale in the process rising, local S-CSCF is routed to E-MSC by the caller event trigger standard that triggers among the iFC with the session invitation message, and E-MSC carries out the signaling protocol conversion, and the IMS signaling is converted to the CS signaling, sets up to call out with far-end to be connected; Flow process shown in Figure 6 specifically comprises the steps:

601, the UE that successfully carries out local registration carries calling number and called number to local P-CSCF transmission session invitation message in this message;

602, local P-CSCF transmits session invitation message according to the routing iinformation that writes down in this UE registration process to local S-CSCF;

603, receive session invitation message after, it (is that local S-CSCF does not call out control that local S-CSCF triggers third party call control according to the caller event trigger standard among the iFC, and call out control by E-MSC), session invitation message is routed to E-MSC;

604, E-MSC (for example calls out control according to the user data that obtains in this UE registration process to calling, judge whether to allow this UE to make a call), call out and send 200OK message (not shown) to UE after control is finished, to set up the media bearer (IP carrying) between UE and the E-MSC; Send initial address message (IAM) according to called number to the PSTN at called subscriber place then, carry calling number and called number in this message.

605, during the called user terminal ring, PSTN finishes message (ACM) to the E-MSC return address;

Mutual through step 604 and 605 set up the media bearer (CS carrying) between the PSTN at E-MSC and called subscriber place.

606～608, E-MSC finishes the ALERTING message that message (ACM) converts SIP to the address of circuit domain, and ALERTING message is transmitted to call subscriber terminal (UE) by local S-CSCF and local P-CSCF;

609, behind the called subscriber's call establishment among the PSTN, the response message (ANM) to E-MSC transtation mission circuit territory;

610～612, receive the response message (ANM) of circuit domain after, E-MSC connects the media bearer between itself and call subscriber terminal (UE) and far-end PSTN, and sending response message (200OK message) to call subscriber terminal (UE) by local S-CSCF and local P-CSCF, subscriber call is answered.

Fig. 7 carries out the method flow diagram of exhaling eventually for adopting system architecture of the present invention; Exhaling in the process eventually, exhale the request of setting up (initial address message) end of receiving circuit domain after, E-MSC initiates the SIP session to called subscriber (UE) and sets up request (session invitation message) as the user agent, finishes call establishment; Method shown in Figure 7 comprises the steps:

When 701, PSTN called out the UE (called subscriber) roamed into local IMS system, PSTN sent initial address message (IAM) to the GMSC of this called subscriber's home network, carries calling number and called number (being the number of UE) in this message;

702, after the GMSC of called subscriber's home network receives initial address message, send route requests to the HSS/HLR of called subscriber's home network, to obtain called subscriber's routing iinformation;

703, HSS/HLR knows that according to the position updating request (step 407) that is sent by E-MSC in called subscriber (UE) registration process called subscriber's current roaming is in the local IMS network of E-MSC administration, therefore send the request of Providing Roaming Number to E-MSC, wherein comprise called number;

704～705, receive the request of Providing Roaming Number after, E-MSC distributes one to point to local roaming number, preserves the corresponding relation of roaming number and called number; And roaming number being returned to the HSS/HLR of called subscriber's home network by response message, the HSS/HLR of called subscriber's home network returns to GMSC with roaming number again;

706, GMSC sends initial address message (IAM) according to roaming number to E-MSC, so that route the call to E-MSC, carries above-mentioned roaming number (as called number) and dialing number information in this message;

707, receive initial address message (IAM) after, E-MSC judges that the called number in this message is the roaming number that this network element distributes, the called number of preserving before therefore finding according to this roaming number; E-MSC calls out control according to the user data that obtains in called number and this UE registration process to calling, calls out the roaming number that uses after control is finished in this called number (being the number of UE) replacement initial address message; And send session invitation message to called subscriber (UE) by S-CSCF, call out to set up, and set up media bearer (IP carrying) between E-MSC and called user terminal (UE); Carry called number (being the number of UE) and calling number in the above-mentioned session invitation message;

708, S-CSCF transmits session invitation message by P-CSCF to called user terminal (UE) according to the IP address and the routed path of user's registration;

709～710, after called user terminal (UE) ring, UE sends the SIP ALERTING message by P-CSCF and S-CSCF to E-MSC;

711～712, after E-MSC received ALERTING message, message (ACM) was finished in the address that is converted into circuit domain, and it is sent to the PSTN at calling subscriber place by GMSC;

So far, finish the mutual of message through above-mentioned initial address message and address, E-MSC has set up the media bearer (CS carrying) between the PSTN at itself and calling subscriber place.

713～714, behind called subscriber's call establishment, UE sends the SIP response message by P-CSCF and S-CSCF to E-MSC;

715～716, after E-MSC receives the SIP response message, connect the media bearer between E-MSC itself and called user terminal (UE) and PSTN, and the SIP response message is converted to the response message (ANM) of circuit domain, send to the PSTN at calling subscriber place by GMSC, finish the foundation of IMS session service.

Claims

1. the service implementation method of an IP Multimedia System network, it is characterized in that, when the user equipment (UE) that is in roaming state by local IP Multimedia System IMS network Proxy Call Session Control Function P-CSCF and service call conversation control function S-CSCF after the E-MSC of enhancing mobile switching centre of local IMS network successfully registers, this method comprises:

2. the method for claim 1 is characterized in that,

After described E-MSC receives described initial address message, also call out control, call out control and finish the described session invitation message of back transmission according to the user data of the described UE of this locality storage.

3. method as claimed in claim 2 is characterized in that,

Described E-MSC obtains and stores the user data of described UE in the following way:

Described E-MSC stores the user data of described UE.

4. the method for claim 1 is characterized in that,

Described E-MSC sets up described IP media bearer by sending described session invitation message.

5. the method for claim 1 is characterized in that,

Described E-MSC and described PSTN finish the described CS media bearer of setting up alternately of message by described initial address message and address.

6. the business realizing system of an IP Multimedia System network, this system provides professional as visited network for the UE that is in roaming state; This system comprises: P-CSCF, S-CSCF, E-MSC; Wherein:

7. system as claimed in claim 6 is characterized in that,

Described E-MSC also is used for after receiving described initial address message, calls out control according to the user data of the described UE of this locality storage, calls out control and finishes the described session invitation message of back transmission.

8. system as claimed in claim 7 is characterized in that,

Described E-MSC also is used for the registration process at described UE, after receiving the register requirement of described S-CSCF transmission, HSS or HLR to the home network of described UE send position updating request, obtaining the user data of described UE, and store the user data of the described UE that described HLR or HSS return.

9. system as claimed in claim 6 is characterized in that,

10. system as claimed in claim 6 is characterized in that,